1. Field of the Invention
The present invention relates to insulating devices for beverage containers and more particularly, to insulating beverages and foods by using air as the insulator.
2. Background and Related Art
Disposable cups are routinely used in fast food and roadside restaurants to contain both hot and cold drinks. Because such cups have relatively thin walls, insulation is poor. As a result, the cups in which hot beverages are served are often too hot to hold comfortably, and the outside surface of cups in which cold beverages are served often accumulate moisture also making the cups difficult to hold, thus causing the holder's hand and the table to become wet. In addition, cold drinks warm quickly and hot drinks lose heat rapidly.
In response to the need for a better beverage insulator, various types of disposable cardboard and paper sleeves have been used. The sleeves are sized to slide onto the outside of a beverage cup and are held in place by friction. The wide-diameter end of the typical beverage cup prevents the sleeve from sliding off the cup while the cup is being held. However, such devices are poor insulators because they are generally thin. Moreover, the close contact with the cup causes additional heat transfer to the outside of the insulator. Additional insulation is needed at the bottom of beverage cups because the fluid has been there for a longer period of time. Also, such devices typically cover any printable material on the outside of the cup, resulting in a lost opportunity for advertising. While some transparent insulators have been created, they also lose effectiveness as insulators because of the close contact with the cups and the conductive material out of which they are typically made. Some of the more effective insulators are too bulky and take up too much storage space in small convenience stores, thus making the disposable cups too big to fit in most cup-holders. Another problem with most disposable cups is that since typical cups have narrow bases, they are unstable. Thus, there is a great need in the beverage industry for cups with better insulation and overall improvement.
To solve the problem of difficulty in gripping either hot drinks or cold drinks that accumulate moisture on the outside of the cup, some disposable cups include handles. Unfortunately, the problem with handles is that they are typically made out of paper or other sheet-like material and they lack sufficient strength to hold the cup in an upright position when the user is holding the cup by the handle. In other words, the weight of the cup can cause the handle to sag or tear such that the cup will tilt, spilling the beverage.